The present invention relates to an electric field measuring system used primarily for measuring electric fields in the atmosphere in outdoor environments, but the features are likely to find application in other applications where the measurement and study of low frequency electric fields is desired. This invention is intended to improve the sensitivity and accuracy of electric field measurement and improve the use of computer equipment to perform a greater variety of management, maintenance, equipment and environment warnings and achieve improved design of field sensing components. Throughout this specification there will be reference to an overall system of several separately located sensors. The term sensor is used to refer to a complete hardware device and circuitry therefor for one sensing location which is often referred to as a field mill or field meter. Reference herein to sensing head is directed principally to the arrangement of plural cooperating electrodes which directly interface with the lines of force of the electric field. Because the fields are essentially DC fields, the sensing head typically embodies a mechanical modulating device and the sensor embodies demodulation to provide an output signal indicating both amplitude and sign of the field being measured.